Early attempts were unsuccessfully made to synthesize .alpha.-amino acids or derivatives thereof by reacting a Schiff base or a nitrile with carbon monoxide and hydrogen. [Bull. Chem. Soc. Japan 33 (160) 78].
U.S. Pat. No. 3,766,266 to Wakamatsu discloses a method of producing an N-acyl-.alpha.-amino acid which comprises holding an aldehyde, an amide of a carboxylic acid and carbon monoxide at a temperature of 10.degree. to 300.degree. C. and a pressure of at least 500 atm. in the presence of a carbonylation catalyst until said N-acyl-.alpha.-amino acid is formed.
In Chem. Comm. 1540 (1971), Wakamatsu, et al. first disclose a cobalt-catalysed reaction which gives various N-acyl amino-acids from an aldehyde, an amide and carbon monoxide. In this disclosure, while benzaldehyde was used as the starting aldehyde, there was no corresponding .alpha.-phenyl-substituted amino acid obtained. Instead of the expected amino acid product, a imine was obtained by a simple "amination" reaction. Dicobalt octacarbonyl was used as the catalyst although the recovery of such metal was not mentioned.
An article by Parnaud, et al., in Journal of Molecular Catalysis, 6 (1979) 341-350, discusses the synthesis potential and the catalytic mechanism for the reaction wherein N-acyl-.alpha.-amino acids are produced by reacting an aldehyde, CO and an amide in the presence of dicobalt octacarbonyl.
In amidocarbonylation, the aldehyde can be generated in situ from allyl alcohol, oxiranes, alcohols and olefins followed by the reaction with an amide and carbon monoxide to produce an N-acyl-.alpha.-amino acid.
A related Patent, U.S. Pat. No. 3,996,288 discloses that when an alcohol or certain of its ester derivatives is held at 50.degree. C. to 200.degree. C. and 10 to 500 atm. in the presence of hydrogen, carbon monoxide, the amide of a carboxylic acid and a carbonylation catalyst, an aldehyde having one more carbon atom than the alcohol or ester is formed in good yield. If the amide has at least one active hydrogen atom on its amide nitrogen, it further reacts with the aldehyde and carbon monoxide to form an N-acylamino acid.
Hirai, et al. discuss a process for combining the transition metal catalyzed isomerization of allyl alcohol to aldehyde and cobalt catalyzed amidocarbonylation to provide a route from allylic alcohols to N-acyl-.alpha.-amino acids. See Tetrahedron Letters, Vol. 23, No. 24, pp. 2491-2494, 1982.
U.S. Pat. No. 4,264,515 discloses a process for obtaining terminal N-acyl-.alpha.-amino acids by a reaction catalyzed by a cobalt carbonylation catalyst wherein the aldehyde is produced in situ from olefins and CO/H.sub.2 mixtures. An unsaturated vegetable oil or C.sub.8 -C.sub.30 mono olefinic compound is reacted with an amide, carbon monoxide and hydrogen in the presence of a cobalt catalyst. The process is operated in one step and provides for increased selectivity.
In amidocarbonylation, various aldehydes have been disclosed as reactants, however, the potentials of amide reactants in terms of preferred structures or substituents has not been well understood. For example, Wakamatsu in his first report of amidocarbonylation reported that the N-acyl-.alpha.-amino acid synthesis can be carried out using a monosubstituted amide. But, Parnaud in J. Mol. Cat. b, (1979) 341-350 reported the attempted reaction of butyraldehyde and N-(.alpha.-phenylethyl)acetamide and no norvaline derivative was formed when the reaction was carried out at temperatures between 100.degree. and 180.degree. C.
The synthesis of a cyclic-amidocarboxylic acid requires cyclic amides, such as 2-pyrrolidone and a substituted amide. There is nothing taught or suggested in the art to predict the outcome of this reaction. It was surprising that the reaction selectively produced two major products. Both products can be used as monomers for synthesizing novel polyamides by polymerization.
This invention discloses the synthesis of amino acid derivatives from cyclicamides, a monomer for polyamides such as Nylon 6,paraformaldehyde and syngas. These products could be hydrolyzed to a novel monomer such as an amino dicarboxylic acid.